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Full-State-Constrained Non-Certainty-Equivalent Adaptive Control for Satellite Swarm Subject to Input Fault

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IEEE/CAA Journal of Automatica Sinica 2022年第3期9卷 482-495页

作者： zhiwei hao Xiaokui Yue haowei Wen Chuang Liu National Key Laboratory of Aerospace Flight Dynamics School of AstronauticsNorthwestern Polytechnical UniversityXi’an 710072China IEEE

Satellite swarm coordinated flight(SSCF)technology has promising applications,but its complex nature poses significant challenges for control *** response,this paper proposes an easily solvable adaptive control scheme to achieve high-performance trajectory tracking of the SSCF system subject to actuator efficiency losses and external *** existing adaptive controllers based on the certaintyequivalent(CE)principle show unpredictability and nonconvergence in their online parameter *** overcome the above vulnerabilities and the difficulties caused by input failures of SSCF,this paper proposes an adaptive estimator based on scaling immersion and invariance(I&I),which reduces the computational complexity while improving the performance of the parameter ***,a barrier Lyapunov function(BLF)is applied to satisfy both the boundedness of the system states and the singularity avoidance of the *** is proved that the estimator error becomes sufficiently small to converge to a specified attractive invariant manifold and the closed-loop SSCF system can obtain asymptotic stability under full-state ***,numerical simulations are performed for comparison and analysis to verify the effectiveness and superiority of the proposed method.

关键词： Dynamic scaling full-state constraints input faulttolerance non-CE adaptive control satellite swarm

Orbital maneuver strategy design based on piecewise linear optimization for spacecraft soft landing on irregular asteroids

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Chinese Journal of Aeronautics 2020年第10期33卷 2694-2706页

作者： zhiwei hao Yi Zhao Ying CHEN Qiuhua ZHANG Department of Astronautical Science and Mechanics Harbin Institute of TechnologyHarbin 150001China Beijing Institute of Control Engineering Beijing 100190China

Recently,asteroid exploration becomes an important branch of human’s deep space *** this paper,a piecewise linear optimal orbital maneuver strategy is designed for a spacecraft soft landing on irregular-shaped ***,the space around an irregular asteroid is converted into several grid units,and the gravitational field of the asteroid is linearly fitted in each ***,the soft-landing orbital maneuver strategy design problem is formulated as a piecewise linear optimal problem,and further transferred into a family of two-point boundary value problems,which can be solved using collocation ***,a corresponding algorithm is developed to obtain the piecewise linear optimal maneuver strategy,which is proved to be able to achieve the soft-landing mission *** results show that the error of the model linearization is small enough,while the calculation efficiency is remarkably improved,and the robustness of maneuver strategy is also improved.

关键词： Irregular gravitational field Optimal control Orbital locations Piecewise linear techniques Soft landing

Risk analysis of extended reach wells in the Liuhua Oilfield,South China Sea,based on comprehensive fuzzy evaluation method

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Petroleum Science 2009年第2期6卷 172-175页

作者： Zhang Hui Gao Deli hao zhiwei MOE Key Laboratory of Petroleum Engineering China University of Petroleum Beijing 102249 China

Drilling engineering has great uncertainty and it always involves huge investment and high risk. Risk analysis of extended reach drilling （ERD） is very important to prevent complex failures and to improve drilling efficiency. Nowadays there are few reports on how to analyze quantitatively the drilling risk for extended reach wells （ERWs）. Based on the fuzzy set theory, a comprehensive fuzzy evaluation model for analyzing risks of ERD is proposed in this paper. Well B6ERW07 is a planned 8,000-meter ERW with a high ratio of horizontal displacement （HD） to vertical depth （VD） in the Liuhua Oilfield, the South China Sea, China. On the basis of the evaluation model developed in this study, the risk for drilling Well B6ERW07 was evaluated before drilling. The evaluation result shows that the success rate of drilling this well is predicted to be 51.9%, providing important rational and scientific information for the decisionmakers.

关键词： Extended reach well risk analysis comprehensive fuzzy evaluation weight value

Simulator of pyroshock environment and effect rules of its adjustable parameters

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Chinese Journal of Aeronautics 2020年第2期33卷 609-620页

作者： Hongda Zhao Jifeng DING Wei LIU zhiwei hao Yi SUN Qiuhua ZHANG Yizhi LIU School of Astronautics Harbin Institute of TechnologyHarbin 150001China Institute of Spacecraft System Engineering China Academy of Space TechnologyBeijing 100094China

During the launching of spacecraft,the on-board devices will undergo a series of pyroshock *** order to verify the reliability of these devices under these pyroshock environments,all of them are needed to take the shock test before *** paper has carried out an in-depth research on the simulation method of the pyroshock based on the true explosive *** this study,a simulator containing multiple adjustment parameters is presented and the safety is considered by the design of the protective *** the working process of this setup is simulated with the explicit dynamic codes *** more,the effects of the adjustment parameters on the three factors of shock Response Spectrum(SRS)of the resonant board are explored *** rules achieved in this paper are verified by a typical *** results indicate that the improved simulator can avoid the danger of explosive and make full use of the advantage of actual explosive *** the test condition can be quickly realized at the simulator according to the effect rules of the three adjustable parameters.

关键词： Adjustable parameters Maximum Expected Flight Environment(MEFE) Protective cover Pyroshock Shock Response Spectrum(SRS)

Constructive Approximate Nash Equilibrium for In-Orbit Target Enclosing with Collision Avoidance and Full-state Constraint via Nonzero-Sum Differential Games

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Guidance,Navigation and Control 2024年第3期4卷 166-190页

作者： Bosong Wei Xiaokui Yue zhiwei hao Zongcheng Liu School of Astronautics Northwestern Polytechnical University School of Aviation Engineering Air Force Engineering University

The problem of in-orbit cooperative target enclosing involving N thrust-limited satellites under collision avoidance and maneuver amplitude constraints is studied. In order to find global optimal trajectories for target enclosing task with all constraints above, by integrating the collision threat and maneuver boundaries into a novel nonlinear cost functional, the studied target enclosing problem is described as a nonlinear nonzero-sum differential game. Further, to avoid iterative calculations caused by traditional nonlinear-game-solving methods, an approximate solution which can be constructed directly is designed. Then the approximate Nash equilibrium strategies can be educed by the constructive approximate solution for the proposed nonzero-sum game. Analysis shows that the proposed control strategies can asymptotically approach the exact one and can ensure a zero-error tracking of the enclosing *** results illustrate lower time costs and better enclosing accuracy while the collision avoidance and maneuver amplitude constraints are satisfied simultaneously.

关键词： Approximate Nash equilibrium asymptotic stability differential game invariant manifold target enclosing

Globularization Mechanism and Near Isotropic Properties in Subcritical Heat‑Treated Ti6Al4V Fabricated by Directed Energy Deposition

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Acta Metallurgica Sinica(English Letters) 2023年第6期36卷 937-948页

作者： Guohao Zhang zhiwei hao Meng Wang Xufei Lu Zhuang Zhao Qian Wang Xin Lin Jing Chen Weidong Huang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China MIIT Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design Northwestern Polytechnical UniversityXi’an 710072China International Center for Numerical Methods in Engineering Universidad Politecnica de Cataluna08034 BarcelonaSpain Institute of Machinery Manufacturing Technology China Academy of Engineering PhysicsMianyang 621054China

Microstructure with globularαphase is desirable as it contributes to preferable comprehensive mechanical properties for titanium ***,titanium alloys fabricated by directed energy deposition(DED)are mainly characterized by the lamellarαphase within the basket-weave microstructure,which often leads to severe anisotropy and inferior low cycle fatigue(LCF)*** address this,the subcritical annealing and the cyclic annealing were applied to DED Ti–6Al–4V in order to achieve the transformation from the lamellarαphase to the globularα*** microstructural characteristics and the globularization behavior ofαphase during heat treatment were *** results show that the aspect ratio ofαis significantly decreased with the subcritical annealing due to the coarsening of lamellarα.Furthermore,the globularαis obtained with the cyclic annealing as a combination result of the termination dissolution and the side surface growth of the lamellarα.These contribute to a pronounced reduction of 85.4%in the ductility anisotropy,compared with the as-built specimens,and superior comprehensive mechanical properties including LCF are achieved with the formation of globularα.

关键词： Directed energy deposition Ti-6Al-4V Subcritical heat treatment Coarsening Globularization

Effect of cyclic heat treatment on microstructure and mechanical properties of laser aided additive manufacturing Ti-6Al-2Sn-4Zr-2Mo alloy

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Advanced Powder Materials

Advanced Powder Materials 2022年第1期1卷 59-66页

作者： Shang Sui Youxiang Chew zhiwei hao Fei Weng Chaolin Tan Zhenglin Du Guijun Bi Singapore Institute of Manufacturing Technology A∗STAR73 Nanyang Drive637662Singapore State Key Laboratory of Solidification Processing Northwestern Polytechnical University127 West Youyi RoadBeilin DistrictXi'an Shaanxi710072China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical University127 West Youyi RoadBeilin DistrictXi'an Shaanxi710072China

Globularαphases can significantly improve the ductility of titanium *** heat treatment(CHT)has been proved to be an effective way to induce the formation of globularαphases inα+βtitanium alloy Ti-6Al-4V fabricated by laser aided additive manufacturing(LAAM).However,there is no prior research reporting methods for obtaining globularαphases in LAAM-built near-αtitanium *** work investigated the cyclic heat treatment(CHT)procedures suitable for the LAAM-built near-αtitanium alloy Ti-6Al-2Sn-4Zr-2Mo(Ti6242)to attain the globularα*** results show that 980℃ is the most suitable upper temperature limit for ***,it is difficult to achieve a high volume fraction of the globularαphases in the LAAM-built Ti6242 alloys through CHT,which is ascribed to the low composition gradient caused by moreα-stabilizing elements and fewerβ-stabilizing *** as-built sample demonstrated elongation of 6.3%,which is lower than the AMS 4919J standard(elongation≥10%).After 980℃ CHT and 980℃ CHT with solution heat-treatment,the formation of the globularαphases significantly increased the elongation to 13.5%and 12.9%,*** the mechanical strength is reduced after heat-treatment,the room-temperature tensile properties still exceed the AMS 4919J *** examination showed that the as-built sample exhibited a mixed brittle and ductile fracture behavior,while the 980℃ CHT and 980℃ CHT with solution heat-treated samples displayed ductile fracture.

关键词： Cyclic heat treatment Globularαphase Ti6242 alloy Laser aided additive manufacturing Room-temperature tensile properties

NEW DOOB'S MAXIMAL INEQUALITIES FOR MARTINGALES

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Acta Mathematica Scientia 2023年第2期43卷 531-538页

作者：郝志伟李丽波 School of Mathematics and Computing Science Hunan University of Science and TechnologyXiangtan 411201China

Let 1≤q≤∞,b be a slowly varying function and letΦ:[0,∞)■[0,∞)be an increasing convex function withΦ(0)=0 and■Φ(r)=∞.In this paper,we present a new class of Doob’s maximal inequality on Orlicz-Lorentz-Karamata spaces LΦ,q,*** results are new,even for the Lorentz-Karamata spaces withΦ(t)=tp,the Orlicz-Lorentz spaces with b≡1,and weak Orlicz-Karamata spaces with q=∞in the framework of LΦ,q,b-Moreover,we obtain some even stronger qualitative results that can remove the△2-condition of Liu,Hou and Wang(Sci China Math,2010,53(4):905-916).

关键词： martingales Doob's inequality Orlicz-Lorentz-Karamata spaces convex functions

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空战中的多目标威胁评估方法

弹箭与制导学报 2016年第1期36卷 177-181页

作者：郝志伟中国空空导弹研究院河南洛阳471009

针对传统空战多目标威胁评估难以满足准确性、实时性的缺陷与不足,提出基于模糊集与证据理论相结合的空战多目标威胁评估方法。该方法通过合理设置隶属度函数计算各威胁指标的威胁度基本概率赋值,使用改进的证据合成规则代替传统Dempste... 详细信息

针对传统空战多目标威胁评估难以满足准确性、实时性的缺陷与不足,提出基于模糊集与证据理论相结合的空战多目标威胁评估方法。该方法通过合理设置隶属度函数计算各威胁指标的威胁度基本概率赋值,使用改进的证据合成规则代替传统Dempster组合规则对其进行指标间融合及时域融合;采用加权求和的方法计算空中目标的威胁值并排序。最后给出仿真算例,验证了该方法的有效性。

关键词：威胁评估证据理论模糊集理论威胁排序